Certain types of cellular cysteine proteases may play an important role in modulating the activity of G-protein coupled receptors. The activity of this class of enzymes is closely regulated by cytoplasmic and nuclear inhibitors. The interaction of these inhibitors with the target proteases is in part mediated by strong hydrophobic interactions. The effects of ethyl alcohol exposure on cysteine protease activity has been studied in cell culture utilizing a PC12 cell line. Activity of these proteases appears to be strongly affected by alcohol exposure.